When I'm on-call, walking the well-lit hallways between clean and spacious patient rooms, I find it reassuring that there's an operating room down the hall, a blood-bank on another floor, and a host of well-trained nurses and anesthesiologists nearby.

During the eight years I trained to be an obstetrician, I learned how to handle the rare complications -- massive hemorrhage, separation of the placenta, rupture of the uterus -- that occur in an instant and can cause lifelong disability or even death. I learned to depend on teamwork and the massive and expensive resources available in a well-appointed hospital. It is anathema to everything I learned that childbirth would occur anywhere else.

Although the overwhelming majority of American women see childbirth like I do, there is a group of women and their partners who see things entirely differently. Childbirth, to them, is a natural event that women have managed at home for all of history (until the past several decades). Hospital births are unnatural and 'medicalized,' and much more likely to lead to a cesarean delivery. A whole 'home birth' movement has grown up to support these women.

I was responsible for Laura and her fetus, and it was my job to deliver a healthy baby and keep Laura safe as well. I felt set up for a calamity.

Published evidence suggests that while women who deliver at home are less likely to suffer the consequences of medical interventions -- everything from c-section to maternal infection -- babies born at home are nearly three times more likely to die than babies born in the hospital.

On a recent morning, a woman expecting her first baby began having uterine contractions and, instead of calling an obstetrician, called her lay midwife. The woman, who we'll call Laura because she didn't want her name used, planned to labor at home. Soon, the midwife arrived and supported her through labor, intermittently checking to make sure she could hear the baby's heartbeat using a hand-held Doppler ultrasound device. Besides the Doppler and a thermometer she used occasionally to check Laura's temperature, the lay midwife focused on keeping Laura as comfortable as possible through the unremitting contractions.

By afternoon, Laura's cervix was fully dilated and she began to push. Two hours -- the time-frame most obstetricians allow before they begin to worry -- came and went, and still Laura pushed. Except for the prolonged and arduous process, everything else seemed fine. Laura's baby's heartbeat was normal and there was no evidence -- based on the temperature readings -- that an infection was setting in, so Laura pushed on. But when eight hours had passed, Laura's lay midwife began to worry that perhaps Laura's baby wouldn't be born -- at least not at home. So she picked up the phone and called 911.

Laura's arrival on my unit represented a clash of obstetric cultures. She had been pushing for eight hours, which in my view was extremely dangerous (I would have intervened or recommended a cesarean hours earlier). Now, I was responsible for Laura and her fetus, and it was my job to deliver a healthy baby and keep Laura safe as well. I felt set up for a calamity.

Laura wasn't any happier than I was. She had planned a home birth and was now in a hospital being cared for by a strange doctor she had never met who had a scowl on his face. And in the hospital, the lay midwife who had neither formal training nor recognized credentials, had no professional standing whatsoever.

Given what we perceived to be an urgent and dangerous situation, my colleagues came at Laura from all sides. We started an intravenous line, connected her to monitors that tracked the baby's heartbeat and her contractions (and as a consequence required her to remain in a hospital bed). We drew blood, took her pulse, temperature, and blood pressure. Laura agreed to all of these maneuvers, but she wasn't happy about any of them. Her husband and the lay midwife stood to the side and watched, slightly overwhelmed.

It would have been easy to tell Laura that a cesarean was recommended given how long she had pushed, but I knew it was the last thing she wanted, so I explained that we could try some other interventions first. We hung a liter bag of saline on an IV pole and dripped Pitocin into her line in order to strengthen the contractions (her uterus was exhausted at this point and needed reinforcement). To measure the contraction strength, I threaded a pressure catheter through her cervix and into the uterus.

Then Laura's baby's heart rate started to drop and became difficult to measure so I connected an invasive electrode to the baby's scalp. Finally, as my level of concern for her fetus mounted, I recommended we pull the baby out with a vacuum device. A few minutes later Laura held her healthy baby girl in her arms. Short of a cesarean, she had experienced about as invasive a delivery as modern obstetrics has to offer.

I felt relieved, and really annoyed: relieved that Laura and her baby were completely healthy, and annoyed that I had been forced -- it seemed to me -- to clean up the lay midwife's mess.

Laura and her husband were relieved and annoyed: relieved that their long labor was over and they held a gorgeous daughter, and annoyed that instead of a serene delivery at home, they had experienced an invasive hospital delivery by an obstetrician who was temperamentally quite different from their midwife.

"What will you do next time?" I asked Laura's husband some time later.